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Vulnerabilities

Vulnerability · CVE-2026-4127

The Speedup Optimization plugin for WordPress is vulnerable to Missing Authorization in all versions up to and including 1.5.9.

Published Mar 21, 2026 · catalog updated Jun 17, 2026 · The Speedup Optimization plugin

Check if you run it

No confirmed exploitation is on record for CVE-2026-4127. EPSS is 0.34%. Act only if a listed version of The Speedup Optimization plugin is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (The Speedup Optimization plugin).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium4.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.34%
Remediation
Version ranges on file
Affected products
stated named in the record

The Speedup Optimization plugin for WordPress is vulnerable to Missing Authorization in all versions up to and including 1.5.9. The function, which handles the AJAX action, does not perform any capability check via and also lacks nonce verification. This is in contrast to other AJAX handlers in the same plugin (e.g., and ) which properly check for and capabilities respectively. This makes it possible for authenticated attackers, with Subscriber-level access and above, to enable or disable the site's optimization module by sending a POST request to admin-ajax.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated named in the record<= 1.5.9

How to fix CVE-2026-4127

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-4127. EPSS is 0.34%. Act only if a listed version of The Speedup Optimization plugin is installed.

Which versions are affected?

Compare what you have installed with named in the record <= 1.5.9. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-862: Missing Authorization. EPSS 0.34%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 21, 2026 · NIST NVD

    Detected

    The Speedup Optimization plugin for WordPress is vulnerable to Missing Authorization in all versions up to and including 1.5.9. The function, which handles the AJAX action, does not perform any capability check via and also lacks nonce verification. This is in contrast to other AJAX handlers in the same plugin (e.g., and ) which properly check for and capabilities respectively. This makes it possi

  2. Jun 17, 2026 · NIST NVD

    Updated

    The Speedup Optimization plugin for WordPress is vulnerable to Missing Authorization in all versions up to and including 1.5.9. The function, which handles the AJAX action, does not perform any capability check via and also lacks nonce verification. This is in contrast to other AJAX handlers in the same plugin (e.g., and ) which properly check for and capabilities respectively. This makes it possi

Sources

  • CVE.orgVulnerability recordCVE-2026-4127

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-4127

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-4127

    The Speedup Optimization plugin for WordPress is vulnerable to Missing Authorization in all versions up to and including 1.5.9. The function, which handles the AJAX action, does not perform any capability check via `current_u

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.